The Basics

The boiling point of water is 212 degrees Fahrenheit at sea level. The higher you are above sea level, the lower the boiling point of water, and the sooner water will boil.

Engine cooling systems are pressurized to raise the boiling point of water. For every pound of pressure in the cooling system, the boiling point of the water will raise 3 degrees.

Atmospheric pressure along with outside temperature and humidity also affect the boiling point of water. Water boils when the atmospheric pressure and vapor pressure become equal.

Radiator Construction

The heat transfer ability of metals (the ability of the metal to transfer heat through itself) helps to determine the efficiency of a radiator. On a scale of one to 100, silver is highest in efficiency with a rating in the upper 90's. Copper is also in the upper 90's. Brass (which is an alloy) has a rating in the upper 40's as does aluminum. Lead which is often used to bond brass and copper together has rating in the 20's.

When comparing copper radiators to aluminum radiators, remember that copper transfers heat through itself better than aluminum, so copper is better at moving the heat away from the tubes inside of the radiator. Radiators that are made of copper and brass are generally more efficient than the same size aluminum radiator.

Aluminum radiators are better at transferring heat out of the liquid coolant. Comparing the two types of radiators with the same dimensions; aluminum radiators have the advantage of being physically lighter in weight. With increased airflow an aluminum radiator can be made to be as efficient as a copper radiator. Keep in mind...you must have the airflow to make aluminum radiators work!

There must always be a drop in air pressure between the front side of the radiator and the engine side of the radiator. It is this pressure drop that helps draw the ar through the radiator. High pressure on the engine side of the radiator can greatly reduce... even stop completely, the flow of air through the radiator.

Summary

Plain water is the best dispersant of heat there is. RadiatorWater is also one of the most destructive liquids you can put into the cooling system. Most all of the problems associated with cooling systems (corrosion, electrolysis, rust, etc.) are related to water.

Corrosion reduces the efficiency of the cooling system by reducing the volume of coolant within the system and by restricting the flow of the coolant itself. Antifreeze is added to the cooling system to prevent the freezing of the water in winter and carries the additives necessary to correct the pH of the water which helps to prevent corrosion and electrolysis. The antifreeze itself provides no cooling benefit.

The faster you drive, the more air that flows thorough a radiator is Not true. No matter how fast you drive, the pressure against the front of the radiator is equal to about 40 percent of vehicle speed.

What happens to airflow after it gets through the radiator is just as important as the amount of air that flows through the radiator in the first place!

In most all applications...a thinner radiator works best and will cool better than a thick core radiator because of the increased airflow available through the thin radiator.